>1. Are there any NIST materials available that are certified for stable
You can obtain certified reference materials or materials with recommended
values from the IAEA. Write to:
Analytical Quality Control Services
International Atomic Energy Agency
PO Box 100
and ask for their latest catalogue.
>2. How might I obtain the "most accepted" isotopic numbers for IAEA
>N-1, N-2, and N-3?
Recommended 15N values are:
IAEA-N-1: +0.4 ”
IAEA-N-2: +20.3 ”
IAEA-NO-3: +4.7 ”